1. Field of the Invention
The invention relates to a photographic camera for use with an APS film, and, more particularly, to a photographic camera equipped with a mid-roll-change function which permits a film cartridge with a film partly exposed and partly unexposed to be reloaded therein and automatically place a first unexposed image frame in the correct position of an exposure aperture. The present application is based upon Japanese Application No. 09-066983, which is incorporated herein by reference.
2. Description of Related Art
In recent years new standard photographic films and cameras prepared according to the requirements for what is called an advanced photographic system (APS) have been on the market. In particular, APS film has a magnetic layer coated over the surface thereof on which information including exposure data such as the type of illumination light and focal lengths and picture information such as titles and legends. The APS film is fully rewound within a light-sealed film cartridge after it has been fully or partly exposed and taken to a photoshop for processing and printing. The light-shielded film cartridge is loaded with the processed APS film and returned with or without prints to the customer.
One type of camera which uses APS film is equipped with a unique function called a mid-roll-change (MRC) function which permits the photographer to reload a film cartridge with a portion of the film remaining partly unexposed. This type of camera has a magnetic head for reproducing data recorded on magnetic tracks of the film. When the camera is reloaded with a film cartridge having a portion of the film remaining partly unexposed, it is automatically placed ready for taking a photograph by reading the data recorded on the magnetic tracks through the magnetic reproducing head and advancing the film automatically based on the data until a first unexposed image frame is placed in the exposure aperture.
Meanwhile, motor driven types of modern amateur cameras increasingly employ miniaturization. Many miniaturized motor driven cameras have a film drive motor installed in the interior of a cylindrical hollow film winding spool. However, miniaturization of an APS motor driven camera equipped with the MRC function imposes constraints on the layout of a magnetic recording head and a film drive motor. Specifically, since the APS camera of this kind makes recording of information on exposure data on the magnetic track for the exposed image frame during winding the film on the film winding spool, the magnetic recording head is typically disposed on one side of the exposure aperture close to the film winding spool. The smaller the APS camera is, the closer to the film winding spool the magnetic recording head must be disposed. An APS camera equipped with the MRC function needs to have a magnetic reproducing head, in addition to a magnetic recording head. Most APS cameras of this kind are typically equipped with a single magnetic head used for both recording and reproducing. For these reasons, in an APS camera of this type the magnetic recording/reproducing head is disposed in close proximity to the film winding spool in which a film drive motor is installed and, consequently, the magnetic recording/reproducing head is apt to be adversely affected by external induction noises (magnetic noises) generated by the film drive motor. These noises interfere with reproduced magnetic signals and cause errors in detecting a first unexposed image frame of the film rewound from the reloaded film cartridge.
In order for the APS camera equipped with the MRC function to be miniaturized to a desirable size and also to prevent generation and adverse effects of magnetic noises, it is essential to apply a double- or triple-shield to the film drive motor and the magnetic head. Most APS cameras of this kind are provided with a strictly shielded magnetic recording/reproducing head imposing structural restraints on the camera, which are always undesirable for miniaturization of the camera.
It is an object of the invention to provide a miniaturized APS camera equipped with a MRC function which permits a film drive motor to be simply shielded and also to prevent or significantly reduce external induction noises generated by the film drive motor.
The foregoing object of the invention is achieved by providing an APS camera with a mid-roll-change function of a type which automatically winds a film until a foremost unexposed image frame of an APS film is placed in an exposure position after a fresh film cartridge is loaded in the camera. In addition, the camera automatically winds a film cartridge with a partly exposed APS film contained therein when it is reloaded in the camera. The camera has a film winding spool located at one side of the camera and a film winding/rewinding mechanism including a reversible film drive motor to wind the film onto the film winding spool from a film cartridge located at another side of the camera and to rewind the film into the film cartridge. The camera comprises a magnetic recording head for making a magnetic recording of exposure data relating to exposure of an image frame on a magnetic track for the exposed image frame during advancement of the film after the exposure and a magnetic reproducing head for magnetically reading the exposure data on magnetic tracks for exposed image frames while a partly exposed film is drawn from the film cartridge reloaded in the camera and wound onto the film winding spool. The magnetic reproducing head is located on one side of the magnetic recording head remote from the film drive motor located in close proximity to one side of the camera in a direction in which the film is advanced. The film drive motor is stopped to interrupt drawing of the partly exposed film when the magnetic reproducing head reads no exposed data on the magnetic track to place an unexposed image frame to which the magnetic track belongs in the exposure position. More specifically, the magnetic reproducing head is located in a position where the magnetic reproducing head reads a magnetic track for an image frame prior to placing the image frame to which the magnetic track belongs properly in the exposure position.
In the camera in which the film drive motor is located in close proximity to one side of the camera at which the film winding spool is installed or is installed within the interior of the cylindrical hollow film winding spool, the magnetic reproducing head is located on a side of the magnetic recording head remote from the film winding spool. On the other hand, in the camera in which the film drive motor is located in close proximity to another side of the camera at which the film cartridge is loaded, the magnetic reproducing head is located on a side of the magnetic recording head close to the film winding spool.
The arrangement of the magnetic reproducing head located sufficiently far from the film drive motor makes it easy to isolate the magnetic reproducing head from magnetic noises generated by the film drive motor or to significantly reduce adverse effects of magnetic noises generated by the film drive motor to the magnetic reproducing head and, in addition, permits the magnetic heads and the film drive motor to be simply shielded, a feature which is always desirable for miniaturization of the camera. In the case where the film drive motor is located in close proximity to the side of the camera at which a film cartridge is loaded, the magnetic recording head provides an effect of cleaning the magnetic tracks or removing dust on the magnetic tracks. As a consequence, the magnetic recording head protects the magnetic reproducing head, which is more sensitive to dust as compared with the magnetic recording head, from encountering dust.